README

This library implements a Symfony security firewall listener to authenticate
users based on a single query parameter. This is useful for providing one-click
login functionality in email and newsletter links.

Installation

Compatibility

This library requires Symfony 2.2 or above.

Usage

This library implements authentication provider and firewall listener classes,
which may be plugged into Symfony's security component to intercept requests
and automatically authenticate users based on a single request parameter.

Token

When a user is automatically logged in by a token parameter in the request, they
will be authenticated with an AutoLoginToken instance. In the context of
authorization, this token satisfies IS_AUTHENTICATED_FULLY. Ideally, it would
be possible to restrict the token to IS_AUTHENTICATED_REMEMBERED, but that is
not yet supported. Additional information on these authorization levels may be
found in Symfony's authorization documentation.

Events

The firewall listener may dispatch events if constructed with an
event dispatcher instance.

Interactive Login

Upon successful authentication by a token parameter in the request, an
interactive login core event will be dispatched with the authenticated
AutoLoginToken instance.

Already Authenticated

If a token parameter is present in the request, but the user is already
authenticated, a custom event will be dispatched, which includes the token's
value. After dispatching this event, the listener's default behavior is to
return immediately, since there is likely no work to be done.

A practical use for this event would be to mark a user's email addresses as
confirmed, assuming the auto-login link with the token was only delivered via
email. As a business requirement, the confirmation service might also listen to
the interactive login core event and operate when the authenticated token was an
AutoLoginToken instance.

Note: Unlike the interactive login event, the token parameter in this event
will not have been validated. It will be the responsibility of the listener to
check whether it matches the currently authenticated user. For this reason, it
may be helpful to inject this library's provider class.

Overriding Already Authenticated Users

By default, the listener will only dispatch an event if the user is already
authenticated; it does not override the existing authenticated user. In some
cases, it may be desirable to allow an auto-login link to override an existing
authenticated user. Otherwise, the user would first need to log out before using
the auto-login link. Setting the listener's override_already_authenticated
boolean option to true will enable this behavior.